Manganese dioxide based electrochemical sensor for the detection of nitro-group containing organophosphates in vegetables and drinking water samples

The widespread use of organophosphates in agricultural farms for pest control has raised serious concerns over the quality of food and water available to the common public. As an effort to fabricate a sensitive, selective, cost-effective and non-toxic sensor to detect nitro-group containing organophosphates in and vegetable washings, a simple manganese dioxide based sensor was developed. alpha-Manganese dioxide nano-rods were electrodeposited on platinum disk electrode (MnO2/Pt) and is employed to detect 4-nitrophenyl phosphate (4-NPP). 4-NPP is a model compound that well represents widely used nitro-group containing organophosphates such methyl parathion, parathion, fenitrothion, methyl paraoxon and paraoxon in aqueous medium. Determination of 4-NPP at nanomolar levels was achieved using the fabricated sensor using cyclic voltammetry. The developed sensor was found to show a linear response in the concentration range 100 nM to 900 nM with a Limit of Detection (LOD) of 10 nM and a high sensitivity of 11.68 mu A mu M-1. The sensor showed good selectivity against many of common inorganic ions and two of the major organophosphates: Quinalphos and Dimethoate but the selectivity is poor among other nitro-group containing aromatics. (C) 2020 Published by Elsevier B.V.